Now, what happens is fun. We can assign CSS properties to elements that are different in full-screen mode than regular mode. When in full-screen mode, the browser adds a class name of :-webkit-full-screen to full-screened elements. There’s probably one for Firefox called :-moz-full-screen, and one for other browsers called :-full-screen. How to use it:

As an aside: I noticed something while browsing through videos on Vimeo and YouTube: in this day of excellent HTML5 video, they still use Flash. Why? Because the Flash experience is the same across all browsers. When we try to full-screen a video, regardless of browser, the video instantly becomes full-screen, along with the controls, which behave appropriately. I bet the folks that worked on the Flash control don’t have to worry about detecting what browser the user is in.